1. Field of the Invention
The present invention relates to a single-lens reflex type digital camera and, more particularly, to a chassis mechanism thereof.
2. Related Background Art
The main body of a single-lens reflex camera using a conventional film is formed by coupling the following components: a cartridge chamber for housing a film cartridge, a spool chamber in which a spool for winding up a film is housed, a main body member formed by a coupling portion that couples the cartridge and spool chambers to form a film rail surface, a coupling member for providing auxiliary strength on the lens mount side of the main body member, and a mirror box to which a mount member having a front end face on which a lens device is detachably mounted is attached, as disclosed in, for example, Japanese Utility model Application Laid-Open No. 62-113341.
The mount member and a mirror mechanism are mounted on the mirror box. The mirror mechanism is retractably inserted in a phototaking optical path and designed to reflect a light beam from a lens and guide it to a finder optical system when it is inserted in the phototaking optical path.
As described above, the camera body is separated into the main body member having the rail surface for positioning a film surface and the mirror box for holding the mount member. Even if the main body member and mirror box are coupled to each other, it is difficult to accurately set a flange back which is the distance from the lens mount surface to the film surface.
For this reason, for example, after the main body member and mirror box are coupled to each other, special operation is required for flange back adjustment, e.g., cutting the rail surface of the main body member to attain an accurate flange back. If the main body member is formed by a mold member, the rail surface cannot be cut. In this case, therefore, the flange back must be adjusted by inserting a washer or the like between the main body member and the mirror box when they are coupled to each other, requiring cumbersome operation. Demands have therefore arisen for an improvement to attain an accurate flange back without cumbersome operation and cost required for the operation.
In a digital camera, since a fast-clock CPU is mounted, much noise is produced. For this reason, the camera body is preferably formed by using a metal that effectively suppress noise instead of a plastic material often used for conventional cameras. If, however, the camera body is to be made of a metal, since it has a complicated shape, aluminum die casting or magnesium alloy forming is required, resulting in an increase in the cost of the camera body. Demands have therefore arisen for a technique of suppressing an increase in cost.
According to one aspect of this invention, a camera has a central main body member on which a lens holding member and image taking device are mounted, and the central main body member is coupled to at least one of the front main body member forming the front portion of the camera and the rear main body member forming the rear portion of the camera.
With this arrangement, a camera mechanism can be realized, which can accurately set a flange back and is resistant to external static pressure.
According to another aspect of this invention, the front and rear main body members are formed by metal parts to increase the overall strength of the camera.
In addition, the front and rear main body members are rendered conductive to electric ground to effectively prevent noise generated by the electric part from leaking outside the camera.